Thanks to everyone who clarified that the horrible background noise during the World Cup games is unrelated to the tournament or the sport, but rather comes from horns called vuvuzelas, which are apparently a very popular noise-maker at sporting events in South Africa. There's a little hope, as this article (thanks ColoradoHoudini) says there is talk of banning them because of how irritating folks find them, with the captain of the French team saying it's actually hard to sleep because the vuvuzela playing begins at 6:00 am.